Continuously heated carbon black furnace



y 5, 1959 v E. A. ERICKSON 2,885,269

CONTINUOUSLY HEATED CARBON BLACK FURNACE 2 Sheets-Sheet 1 Filed July 5, 1957.

FlGURE 2 Y b ATTONEY y 1959 E. 'A. ERICKSON 2,885,269

CONTINUOUSLY HEATED CARBON BLACK FURNACE Filed July 5, 1957 2 Sheets-Sheet 2 FIGURE 3 INVENTOR MQSW 1;; w msw BY ATTO NEY .thatcarbon deposits form on 7 older processes all utilize recently evolved to ',consists of passing turbulent zone of hotvdesired type of ca fvantageou's in that lavoid the difficulties hereto T facturing carbon black while crackingcha'mb'er 'to .ing a source of heat I I 'v'vhe'n a hydrocarbon is introduced into the cracking zone.

U r dSt t P or 2,885,269 I CONTINUOUSLY HEATED CARBON BLACK i FURNACE v 1 Edward A. Erickson, Terre Haute, Ind, assignor to Cornmercial Solvents Corporation, Terre Haute, Ind., a corporation of Maryland I Application July 5, 1957, Serial No. 670,165 2 Claims. (Cl. 23-2595) My invention relates to a process for the production of carbon black and more particularly to a process and I V an apparatus for the production of carbon black from hydrocarbons.

Carbon black is produced by the thermal process by intermittently bringing natural gas in contact with hot refractory materials and periodically reheating the refractory materials by burninga combustible gas in contact therewith. This procedure has the disadvantages of lacking continuity, and lacking uniformity of temperature conditions, and has been subject to the further objection the refractory surfaces and- H tend to clog the passages through the checker work.

Attempts have been made to devise continuous manufacturing processes while retaining the advantageous characteristics of the presently used processes, as the low cost hydrocarbon fuels. discloses a continuous process solve this problem. The process the vhydrocarbon feed through a I blast flame gases to obtain the rbon black. While this pr o'cessis adit can use a cheap hydrocarbon fuel and is continuous, it has a serious defectin that excessive amounts of carbon monoxide fa're formedwhen fiame byproducts react with the carbon black. Using the apparatusof my. invention,

US. Patent 2,769,692

I amable to... fore experienced in manu-' s n a dee yd q fuel and operating continuously.

The apparatus 0 two-chamber continuously heated carbon black furnace. One chamber of the furnace contains the heat generating units which are burners shaped to reflect their radiant heat through open ports into the second part of the furnace, the cracking chamber. I The radiant heat from 50, the heat generating units heats the refractory of the.

' crac 'ngtemperatures, thus'furnish-' 1 for the formation! of canbonblack The gas contained in the cracking chamber is separated from the combustion products of the heat generating chamber by a slight pressure differential between the chambers, and by utilizing the reduced pressures resulting from the high speed flow of burned gases through the relative constriction formed by the edge of the circular flame cup and the radiation port edge.

Carbon black is prepared in the process of my invention by heating the cracking chamber of the apparatus .of my invention by burning carbonaceous materials in the heat generating units which are shaped to reflect their radiant heat through the open ports into the cracking chamber. A hydrocarbon feed is continually passed through the cracking chamber at a slightly greater pres- :sure than the pressure maintained in the combustion chamber so that no reaction products from the combustion chamber are allowed to pass into the cracking charnber. In this manner, the combustion byproducts are reference to the accompa separated by an impervi ou chamber 8'is maintained in carbon feed pressure. The feed for the 'is' introduced through 0 l and the combustion pro burner 6 into the combustio s where it is reflected oif I I I .further incr f my presentlnvention' comprises a 45 I, 4

duced to the cracking In' this apparatus, the ,line 5 to flow over combustion chamber 'troduced by means of 'pipe 10' inside of the fuel supply line 5 1: 5:19? t not allowed to come into contact with the cracking chamber feed and substantially no carbon, black is lost as carbon monoxide.

My invention is further described and illustrated by nying drawings. Figure 1 is a vertical cross section of the furnace of my invention along lines 2-2 of Figure 2.

Figure 2 is a horizontal cross section of the furnace taken along lines 1-1 of Figure 1.

Figure 3 is a drawing of a horizontal cross section of a furnace having an alternate configuration from that shown in Figure l.

Figure 4 is a cross section of one type of a combustion chamber.

Referring to Figures 1 and 2, my apparatus consists of a furnace enclosed by a vertically positioned heat resistant refractory wall 1, a heat resistant roof 2, and a heat resistant floor 3. The two chambers of the furnace are s heat-resistant refractory wall 4 positioned within the enclosure. Heat is supplied to the furnace by igniting gas passed through the fuel supply system 5 to the shaped burners 6. The products of the of the combustion chamber 7. The pressure between the combustion ch differential amber 7 and the cracking I part by the damper 9 at the reaction chamber outlet and by control of the hydrocracking chamber the preheater system 10 into the cracking chamber 8 where the heat reflected from the burners 6 is suflicient to .pyrolytica-lly break the hydrocarbons down into hydrogen and carbon black. The carbon black and hydrogen are removed through outlet 11,

passed thr ough a cooling apparatus 12 and into a carbon black collector which is not shown.

Figure 3 shows a carbon black furnace of the type of my invention in which more than one heating chamber is used. In the furnace of Figure 3, the heating fuel ,flows in through the fuel delivery system 5, is burned ducts flow over the edge of the n chamber 7, while the heat 6 into the crackingchamber of a refractory column 13 to ease the heat capacity of the system. i Figure4 shows an apparatus in which the feed is introchamberin an alternate manner. fuel is introduced through the the face of the burner 6 into the i from whence it is removed. The cracking feed, instead of being introduced through a side wall of the reaction chamber as in Figure 1, is inconcentrically situated From the cracking feed I hydrocarbon is fed into the cracking chamber 8"and'the' carbon -black and hydrogen are removed in the same manner as described in Figure l.

As indicated in all the attached drawings, it is preferable to locate the burner 6 in close proximity to the refractory wall 4 to obtain maximum heating and to take advantage of the Bernoulli effect caused by the high speed flow of flame products through the relative constriction between the burner face and the partition wall. It is possible, however, to use a burner having a long focal length and a large port in the partition wall. There is usually a larger loss of cracking feed due to the fact that combustion products are kept out of the cracking chamber with an increased cracking feed loss due to the larger area through which the cracking feed can flow into the combustion chamber. Since it is advantageous to situate the burner 6 a short distance from the refractory partition 4, the focal length of the shaped flame face will determine the size of the radiation ports through which,

is reflected from the burner brick.

velocity combustion .heat is transferred from this surface uniformly and may .transferred by the radiation.

the radiated heat from the combustion chamber passes to the cracking chamber. Where a shaped burner face has a short focal length, the diameter of the radiation port can be much less than the diameter of the burner face. Where a burner face having a long focal length is utilized in the furnace, a radiation port of much larger diameter is required or part of the radiated heat will be reflected back into the combustion chamber causing a loss of cracking efficiency. A burner of short focal length is preferred due to the fact that there is less cracking feed loss through the smaller radiation port.

The apparatus of my invention may be of any desired size. As this is a continuous process, it is not necessary to have a particularly large furnace because of the fact that the furnace can be employed in producing carbon black at all times, no production time being lost due to the time required for a heating cycle.

The size of the carbon black particles formed in the furnace is determined in part by the residence time of the particles at cracking temperatures. Where there is .a long residence time, the carbon black formed tends to be of large particle size while short residence times tend to produce carbon blacks of very small particle size.

The furnace walls, floors and partitions must be made of a temperature resistant refractory material due to the extreme temperatures required for the various pyrolytic processes. I have found that the walls of this apparatus can be made either of checker brick or of a smooth construction. I prefer to use a smooth construction due to the fact that less carbon can be deposited on the smooth surfaces than is deposited in the recesses of the checker I have found that in either instance, where checker bricks are used or where the walls are smooth, catalysts can be incorporated in the walls of the furnace. I have also found that I can insert trays of a catalyst into the furnace, positioned to act as baflle's, with excellent results.

The burners used in my invention consist of heatresistant refractory cup-shaped burners. The cups are shaped like the conventional light reflectors with the buner tip in the middle. The gas-air mixture burns as it leaves the many small ports of the burner tip and sweeps radially across the burner cup surface. The

. inner contour of the cup is shaped so that its surface is always washed by hot combustion products. The refractory cup surface is heated to incandescence by the high products flowing over it. Radiant be directed much as light rays are directed by a light reflector. At 1800" F. and above, 80% of the heat is By using a short focal length, the heat may be transmitted into the cracking chamber through a relatively small opening, much smaller than the diameter of the burner. Generally I maintain the cracking chamber at temperatures in excess of 1500 F., preferably from 2000-3000 F., due to the increased yields resulting from the use of these higher temperatures.

7 Generally, when preparing carbon black in the furnace of my invention", the furnace is heated to cracking temperatures and the crackingffeed is introduced into the cracking chamber under pressure, converted to carbon black and recovered. The pressure at which the feed is introduced into the cracking chamber is governed by variables such as the size of the furnace and the cracking temperature. High temperatures, on the order of 3000" F., require very short residence times when compared with the residence times needed at 2400 F. The

residence time is determined in part by the pressure of the cracking feed introduced into the cracking chamber. After a desired feed pressure is established, the pressure in the-combustion chamber is increased to a pressure just slightly below the pressure maintained in the cracking chamber by control of the flow of combustion products through the combustion chamber exit. This reduces the cracking chamber feed loss.

I prepare carbon black in the furnace of my invention by heating the furnace to 2400 F., by burning a natural gas-air mixture in the burners contained in the combustion chamber; introducing a cracking fuel into the cracking chamber at 30 p.s.i. and raising the pressure of the combustion chamber gases to about 28 to 29 psi by damping the flow of combustion products through the combustion chamber exit; and collecting the carbon black as it passes out of the cracking chamber exit.

Now having described my invention, what I claim is:

1. An apparatus for the production of carbon black which comprises: (a) a refractory furnace divided into at least two chambers by at least one partition, (b) each of said partitions having at least one port therein, (0) at least one of said chambers consisting of a heating chamber and containing at least one heating burner positioned therein and outlet means in each heating chamber in addition to said partition ports for removing heating gases generated by said heating burner, (d) each of said heating burners being shaped to reflect radiant heat through one of the said ports into a separate cracking chamber which does not contain a heating burner, (e) passage means for introducing the cracking feed stock into said separate cracking chamber, and (f) a mass of heat absorptive refractory material in said separate cracking chamber.

2.. The apparatus of claim 1 wherein the mass of heat absorptive refractory material in said separate cracking chamber is applied so as to form the inner surface of .said separate cracking chamber.

References Cited in the file of this patent UNITED STATES PATENTS 986,489 Morehead Mar. 14, 1911 1,307,430 Zimmers June 24, 1919 1,592,474 Szarvasy July 13, 1926 2,704,242 Strauss Mar. 15, 1955 12,790,838 Schrader Apr. 30, 1957 

1. AN APPARATUS FOR THE PRODUCTION OF CARBON BLACK WHICH COMPRISES: (A) A REFRACTORY FURNACE DIVIDED INTO AT LEAST TWO CHAMBERS BY AT LEAST ONE PARTITION, (B) EACH OF SAID PARTITIONS HAVING AT LEAST ONE PORT THEREIN, (C) AT LEAST ONE OF SAID CHAMBER CONSISTING OF A HEATING CHAMBER AND CONTAINING AT LEAST ONE HEATING BURNER POSITIONED THEREIN AND OUTLET MEANS IN EACH HEATING CHAMBER IN ADDITION TO SAID PARTITION PORTS FOR REMOVING HEATING GASES GENERATED BY SAID HEATING BURNER, (D) EACH OF SAID HEATING BURNER BEING SHAPED TO REFLECT RADIANT HEAT THROUGH ONE OF THE SAID PORTS INTO A SEPARTE CRACKING CHAMBER WHICH DOES NOT CONTAIN A HEATING BURNER, (E) PASSAGE MEANS FOR INTRODUCING THE CRACKING FEED STOCK INTO SAID SEPARATE CRACKING CHAMBER, AND (F) A MASS OF HEAT ABSORPTIVE REFRACTORY MATERIAL IN SAID SEPARATE CRACKING CHAMBER. 